Field of the Disclosure
The present invention relates generally to power converters, and more specifically to power converters with secondary switches.
Background
Electronic devices (such as cell phones, tablets, laptops, etc.) use power to operate. Switched mode power converters are commonly used due to their high efficiency, small size, and low weight to power many of today's electronics. Conventional wall sockets provide a high voltage alternating current. In a switching power converter, a high voltage alternating current (ac) input is converted to provide a well-regulated direct current (dc) output through an energy transfer element to a load. In operation, a switch is turned ON and OFF to provide the desired output by varying the duty cycle (typically the ratio of the on time of the switch to the total switching period), varying the switching frequency, or varying the number of on/off pulses per unit time of the switch in a switched mode power converter.
The energy transfer element may have one or more primary windings coupled to the input side of the power converter and one or more secondary windings coupled to the output side of the power converter. Power converters may also include switches as synchronous rectifiers coupled to the secondary side of the power converter.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present disclosure.